ACTG 388 was designed to evaluate two four-drug regimens compared with a three-drug regimen in patients who were relatively treatment naive. Based on the increased complexity and toxicity of four-drug regimens and the resultant negative impact on response as compared with three-drug regimens, studies evaluating simplified potent regimens appear warranted. This study will evaluate simpilified drug regimens designed to enhance virologic activity without necessarily increasing the number of antiretroviral drugs. The study regimens will be assessed for both virologic control and tolerability. The study population will include patients previously enrolled in ACTG 388 and patients with prior advanced HIV disease who received and responded to potent antiretroviral therapy without evidence of virologic relapse.